高含水期多层油藏注水层段划分方法

Reasonable water injection interval dividing of multilayer producing block reservoir with high water cut

多层合采的断块油藏进入高含水期之后,纵向动用程度差异大,层间矛盾突出。分层注水技术能够改善层间矛盾,促进注入水的均衡驱替,而注水层段的合理划分是提高分层注水效果的关键。文中给出了一套分层注水井注水层段的合理划分方法,并编写了计算程序。该方法提出采用各小层吸水指数为注水层段划分的依据指标,建立了层段划分的政策界限;基于各注水层段内吸水指数级差最小化的原则,在满足吸水指数级差相应的政策界限的前提下,应用枚举算法(插板法)进行注水层段的合理划分。通过东辛油田实例验证了此方法能有效降低含水率,改善高含水期油藏注水开发的效果。

Great difference of vertical utilization degree and the interlayer contradiction exist in multiplayer producing block reservoir with high water cut. Separate layer water injection is able to achieve balanced displacement by reducing the contradiction between layers, and the reasonable division of the water injection intervals is the key to improve the effect of separate layer water injection. In this paper, a set of reasonable dividing method of the water injection intervals is proposed and the calculation program is established. This method takes water injection index as the standard of interval division of each layer, and the policy limits of the division of intervals is established. Based on the principle of minimizing the differential of water injection index, the method of enumeration algorithm（fill-in method） is used to divide the water injection intervals to ensure that differential of water injection index to meet the corresponding policy limits. This method is efficient to reduce the water cut and improve the effect of water injection, which is also verified by practical example.